Lowering spring options?

[klodkrawler05]

TLDR: whose running stock style springs instead of coilovers, which are you using and do you have any issues with bottoming them out?

Curious to see what you guys are running or having luck with.

I'm looking for a dual purpose setup for both street and auto-x (probably more emphasis on the street)

I've acquired a full e30m3 suspension setup so I have the ability to adjust roll center to correct for lowering and will do the offset rear subframe bushings.

I've been perusing the e30 spring rate thread and I think my stock 325e springs are:
106 front / 245 rear (baseline/stock height)
the e30m3 springs that I have should be:
140 front / 250 rear (.75/1" lower than baseline height)

Where I'm getting hung up is most lowering spring reviews seem to talk about bottoming issues and being too soft etc etc. What's confusing to me about that is relative to the m3 springs I'm only seeing .5-.75" of additional lowering but spring rates taking a similar increase as 325 to M3:
H&R sport 180 front / 340 rear 1.5" lower than baseline

The IE stage 3 springs seem like they'd really suit the bill at 2" lower than stock and spring rates of 315 front 575 rear but they're out of stock and no sign of when they'll be back.

I'm trying to avoid going to coilover as don't want to modify the NLA front struts but I recently discovered the JOM front coilover sleeve which seems designed to work with unmodified fronts. Something like that might be an option and would allow me to chose better spring rates?

[Jb325is]

The bottoming is an issue because of the physical length of the strut. I don't think modifying e30 m3 struts for coilover would be detrimental to their value at all, unless you're putting BC's in them or something. Remember... It's just a tube. The important stuff is cast.

[FredK]

The front struts are still available, but they've nearly doubled in price to $1500 each. Ridiculous. Modifying them might reduce their value a small amount. I occasionally look at s14.net and the strut housings that do come up often sell very quickly, but the modified ones do not.

You can run GC coilover conversion sleeves on unmodified housings. You sit the height adjuster on the stock spring perch. However, this limits the height adjuster from being adjusted all the way down.

For a dual duty car, I think H&R Race is fine. They're a little soft so you'll have to adopt a smoother autocrossing style. I never bottomed mine out, but I also don't have extremely terrible roads where I live.

For stock diameter springs, the Turner J-stock springs have roughly double the rate of H&R Race. They should be paired with higher damping rate J-stock Bilsteins (which are still available). These are technically streetable, but rough pavement will NOT feel good.

[5Toes]

I have problems with my Suspension Techniques lowering springs where the car just sits too low with gear/people in it. Hard to go camping when your car's resonator is 1/2" off the ground because of the car being loaded down. They are similar to H&R sport in lowering and rate. this is a m42 car with 318 specific springs.

that said, hr sports or ST springs and upgraded sway bars is a great way to roll. a cabrio front bar with m3 links is going to be awesome and cheap. Rear bar you can experiment with, some like to keep it stock or none at all. others go for the 19mm rear bar from IE, etc.

[e30_302]

The front it easy, it's just a normal 5" spring. You can get about any rate and length you want. Go a little soft and pop a spring rubber in for autocross. For the rear I'd get adjustable perches and a 2.5" spring.

[klodkrawler05]

Modifying them might reduce their value a small amount. I occasionally look at s14.net and the strut housings that do come up often sell very quickly, but the modified ones do not.

Yup this bit right here is why I was aiming to keep them un-cut, doesn't matter how/who did the work people always want to be the person to do it themselves :)

I have problems with my Suspension Techniques lowering springs where the car just sits too low with gear/people in it. Hard to go camping when your car's resonator is 1/2" off the ground because of the car being loaded down. They are similar to H&R sport in lowering and rate. this is a m42 car with 318 specific springs.

that said, hr sports or ST springs and upgraded sway bars is a great way to roll. a cabrio front bar with m3 links is going to be awesome and cheap. Rear bar you can experiment with, some like to keep it stock or none at all. others go for the 19mm rear bar from IE, etc.

Thats good to know, I'll steer away from ST springs for this application then. I've got a lifted TDI that I commute with and it usually gets the nod when we go camping.

The front it easy, it's just a normal 5" spring. You can get about any rate and length you want. Go a little soft and pop a spring rubber in for autocross. For the rear I'd get adjustable perches and a 2.5" spring.

Ahah! this is something I didn't know, 5" is the common circle track size so it should be pretty easy to find a spring that will work length/rate wise up front and then a set of adjusters and 2.5's in the back.

Perfect for a dual purpose setup like this! thank you!

[2mAn]

H&R Race / IE3 and be done with it. I love my setup. Get some good struts & shocks to go with it and enjoy.

Ive had IE3 and Bilsteins and it was a great setup, but Im switching to Koni SAs now. Keeping the IE3 as long as I can

[BlackbirdM3]

H&R Race / IE3 and be done with it. I love my setup. Get some good struts & shocks to go with it and enjoy.

Ive had IE3 and Bilsteins and it was a great setup, but Im switching to Koni SAs now. Keeping the IE3 as long as I can

Too soft and too low. The ONLY setup that works that I've found is the Turner J stock springs at 640/1080. This is on a suspension that is lowered as far as it can go without blowing the roll center.

I've tried at least 6 different spring and shock combinations and my current Turner J stock and custom valved Koni Sports are the ONLY ones that didn't bottom out. The one combo that I haven't tried are the Turner J stock valved Bilsteins with the H&R Race springs. The compression damping might be high enough to keep the front end off the bump stops, but I'm not going to bet on it. The J stock valved Bilsteins are at least double the compression damping of normal Bilstein Sports, and 3 times more than my Konis. That said, with the real J stock springs and dampers I'd have to guess the ride will be very harsh. This is why I went with my set of revalved Koni Sports with the rebound damping set full hard (Still a little under damped on the rebound side, but pretty close.)

Combos that I have tried:
-Koni sport springs with bilstein sports and koni sports in the rear. - Poorly balanced, didn't bottom, but didn't handle well either.
-Koni Sport springs with TC Klein revalved Koni Sports- Bottomed all the time, even sweeping corners would bottom the outside suspension. Rebound damping was higher than it needed to be, but the car was planted, till it hit a bump. Broke the front spring hats in the center. Lots of body roll
-H&R race springs, TC Klein revalved Koni sports- bottomed out hard, all the time. Broke front spring hats in the center. Harsh ride due to front end bottoming. Lots of body roll.
-H&R Race Springs with Bilstein Sports- bottomed hard nearly all the time, rebound in the back was far too little. Broke front spring hats in the center. Harsh ride due to front end bottoming. Lots of body roll.
-H&R Race springs with Bilstein sports up front TC Klein Konis in the back. - Bottomed out almost everywhere, rear end was planted. Broke centers out of the upper spring hats. Harsh ride due to front end bottoming. Lots of body roll.
-Turner J stock springs and TC Klein Konis- Doesn't bottom out, car is flat through corners, minimal body roll. Car is perfect, easy to drive and very fast. Rear rebound damping could be a little better, but pretty good as is. The ride is firm, but not harsh. Feels like a sport touring sedan should. Very planted and predictable. I'm really looking forward to running this setup with Hoosier R Compounds in a couple weeks.

At this point the only changes I'm going to make to my suspension is to throw the garbage Ground Control Race camber plates (the top of the line ones) in the trash because they suck. Poorly designed, they contact the tops of the spring hats and rub till the undersides of the strut mounting studs shear off. (I've rewelded mine a couple times now.) The mounts are too short, need to be another 1.25 inches taller so as not to over lower the car. (effectively be the same stack height as the stock strut mounts.) If you are all about show and no go, these are the camber plates for you. Yes the are a solid mount spherical bushing, but that is the least of the designs issue. They flat out don't clear a stock spring hat, and screw up the suspension geometry too much.
I'm going to get a set of Vorshlag camber plates and call it good. Those along with new rear bushings sound make for a perfect suspension for the car.

Will

[JRKOUPE]

Fred nailed some good points.


I ran HR race and GC valved Koni SA for 10 yrs on the track......great great dual duty set up but a bit soft once u get really fast on track


ok on street for sure.....a bit stiff over bad roads....i was always careful.

or u can do c/o's and not have to cut tubes at all.......youll get plenty low if desired by reducing your stack ht w/ a good qual camber caster plate like GC or vorshlag...I have brand NEW Vorshlag plates you can steal.



this is well documented stuff......nothing new

bottoming out like stated is also often due to shock length.......GC frt konis are short, but I used an internal spacer in my strut as I never cut my tubes......

[klodkrawler05]

Fred nailed some good points.

I ran HR race and GC valved Koni SA for 10 yrs on the track......great great dual duty set up but a bit soft once u get really fast on track

ok on street for sure.....a bit stiff over bad roads....i was always careful.

or u can do c/o's and not have to cut tubes at all.......youll get plenty low if desired by reducing your stack ht w/ a good qual camber caster plate like GC or vorshlag...I have brand NEW Vorshlag plates you can steal.

this is well documented stuff......nothing new

bottoming out like stated is also often due to shock length.......GC frt konis are short, but I used an internal spacer in my strut as I never cut my tubes......

I hadn't realized the GC koni's were re-valved, that's worth noting.

I agree that pretty much all of this stuff is documented but in my search's it's always been "bro just do GC's and be done with it broooo" that's great and its certainly a worthwhile option.

I also appreciate your feedback on H&R Race and revalved Konis, that sounds like a setup that might work well for me, my track car is a boosted e46m3 with MCS duals and 800/900lb spring rates. I'm not planning to build the current e30 to be faster or more capable than that car I'd simply like to be able to take my e30 to local events or instructor lapping days when I don't feel like dragging the M and dealing with it's associated extra work becauseracecar.

While some of the info here is re-hashed from previous threads, before this thread I didn't know:
- Front oem style springs were a standard 5" coil spring (those are cheap and easy to find on ebay)
- Some race type camber plates have a thinner stack height than oem type parts.
- GC konis are re-valved from the standard ones.

I can get a half dozen sets of used 5" front coil springs and rear 2.5" coil springs to test various rates for the price of a new set of HR Race so I'll probably head that direction just to have the option to tinker.

I'm also thinking I'll target stock e30m3 ride height minus the stackup height difference of camber plates in front and then a rear ride height that matches. That should hopefully let me use most of the OTS offering's of sport shocks without having such little travel that I'm hitting bump stops all the time.

Thanks for all the comments/help everyone!

[ajhostetter]

I'm sure I'll get flamed for this, but I've had great luck with Vogtland springs (p/n 951018) and Bilstein Sport shocks. Additional mods are an adjustable IE front sway bar set to the most aggressive setting, no rear bar, and GC touring plates set to -2 degrees camber. I'm running the stock 4 lug suspension and it's quite neutral with no understeer and breaks away predictably in corners in my S52 swapped 318is.